Walking-beam and counterbalance construction



w. E. SAXE 2,184,436

WALKING-BEAM AND COUNTERBALANCE CONSTRUCTION Dec. 26, 1939.

3 Sheets-Sheet 1 Filed April 4, 1938 RRIS FOR THE F/RM /4TTORNEV\S.

Dec. 26, 1939. w 5 SAXE 2,184,436

WALKING-BEAM AND COUNTERBALANCE CONSTRUCTION Filed April 4, 1938 3 Sheets-Sheet 2 G6 45 do //VVN7'OR WALTER E. \SAXE HARRIS, K/cchgfos R HARRIS FOR THE FIRM A rro RNE re.

w. E. SAXE 2,184,436

WALKING-BEAM AND COUNTERBALANCE CONSTRUCTION Dec. 26, 1939.

a Shets-Sheet 3 Filed April 4, 193a /NVNTOR WALTER E. \SAXE HARR/sKmc/i Fo TER d HARRIS FOR THE FIRM A Trek/vars.

Patented Dec. 26, 1939 UNETED STATES PATENT OFFICE WALKING-BEAM AND COUNTERBALANCE CONSTRUCTION 14 Claims.

My invention relates in general to mechanism that include lever means for producing straightline reciprocation, more particularly mechanism for such purpose in which the major load is primarily in only one direction of the reciprocation. For the purpose of illustrating the principles involved in my invention, the present disclosure is directed specifically to a mechanism for pumping oil wells, but it is to be understood, as will be apparent to those skilled in the-art, that the principles of my invention may be embodied in various mechanisms for various purposes where straight-line reciprocation is requisite.

An oil well pumping mechanism of the type involved here is built around a walking-beam, the walking-beam being oscillated by power means and being connected at its working end to a string of rods extending down into the oil well. Since the working end of the walking-beam moves in an arcuate path, it is desirable to provide the walking-beam with arcuate means commonly termed a mule-head in tangential engagement with flexible means interconnecting the working end of the walking-beam and the string of rods in the well. In the conventional arrangement, the mule-head required is necessarily of considerable vertical extent, with the result usually that considerable head room is required at the top of the stroke and on the downstroke the mue-head is a hazard to workmen.

An important object of my invention is to reduce the arc or vertical length of the mule-head required for a given pump stroke. In this regard my invention is based on the concept that the arcuate extent of the mule-head. may be materially reduced if the walking-beam has one pivot, concentric with the curvature of the mulehead, that reciprocates in a straight line parallel with the straight-line motion of the pump rods, all the other pivotal connections of the walking-beam shifting as required to accommodate this paralel movement. Since guide means is required to restrict movement of the selected pivot to a straight line, this pivot will be referred to as the guide pivot. The walkingbeam, operating on my principle requires a second pivot anchored or restricted in a manner to permit shifting thereof, as required, to accommodate the straight-line motion of the guide pivot. This second pivot will be termed, for convenience, the fulcrum pivot, but it is recognized that the action of the walking-beam may be analyzed with the guide pivot taken as the 5 fulcrum.

A feature of my invention is that the center of curvature of the mule-head is shortened to the guide pivot instead of extending to the fulcrum pivot. This fact is important, because this radius controls the length of the mule-head. 6

In pumping oil or in reciprocating a string of drill tools, the load on a walking-beam is primarily in one direction of reciprocation. A feature of my invention is the application of counterbalancing forces to' the guide pivot of such a 10 walking-beam and one of my objects is to combine in one structure means to counterbalance the walking-beam load and means to guide the guide pivot.

In such an installation, in addition to counter- 15 balancing the load on the walking-beam, it' is often desirable to provide auxiliary counterbalancing means to equalize the engine load by storing energy when the crank driving the walkingbeam passes through each of its two dead-center :0 positions. A further object of my invention, in the forms herein disclosed, is to provide a unitary fluid-pressure system to serve both thepurpose of counterbalancing the load on the walking-beam and the auxiliary purpose of equalizing the load on the engine.

Other objects and features of my invention will be apparent in the description to follow, taken with the accompanying drawings.

In the drawings:

Fig. 1 is a side elevation partly sectioned of a. pumping unit incorporating my invention;

Fig. 1a is a fragmentary view similar to Fig. 1 showing how certain elements in Fig. 1 may be altered to form a modification of my invention; 35

Fig. 2 is a horizontal section taken along the broken line 22 of Fig. 1;

Fig. 3 is an end view of the unit partly sectioned;

Fig. 4 is a fragmentary view in side elevation showing a fulcrum pivot construction that may be employed in a modification of my invention;

Figs 5 is a diagrammatic view to indicate the construction of a second form of my invention;

Fig. 6 is a diagrammatic view showing how the configuration of the mule-head of Fig. 1 may be altered for the purpose of reciprocating pump rods in a non-vertical direction.

Fig. 7 is a fragmentary view of a walkingv beam construction that may be employed in another form of my invention;

Fig. 8 is a section through a bearing of Fig. '7- taken as indicated by the line 8-8 of Fig. '7;

and

Fig. 9 isa diagrammatic view to illustrate the principle of operation in the walking-beam of Fig. 7.

Fig. 1 shows a typical installation of the preferred form of my invention for operating a deep well pump conventionally shown at l6 through the medium of a string of sucker rods H, the pump being in a string of tubing l2 in the well casing 13. At the top of the well is a casing head I4 having the usual lateral pipes l5 and also the usual vertical pipe l6 having a lateral branch I! through which oil is delivered from the well. The uppermost sucker rod, the polish rod l8, passes through a packing gland l9 in the pipe l6.

The mechanism for actuating the well pump is mounted on a box-like frame 20 on foundation blocks 22, the frame supporting on its upper side a platform 23. A walking-beam 24 is pivotally mounted on and guided by vertically movable means generally designated by the numeral 25. In the particular construction shown in the drawings, the walking-beam comprises a pair of side plates 26 having trunnions 21 to provide a fulcrum pivot at one end of the beam, trunnions 28 at an intermediate point to provide a drive pivot for actuating the beam, and guide bearings 29 to receive trunnions 30 of the vertical guide means 25, the trunnions 30 providing the guide pivot for the walking-beam. The guide pivot divides the beam into a forward arm 32 having its working end extending to the axis of the well casing, and a rearward arm 33 having the fulcrum pivot 21.

The forward arm 32 is operatively connected with the sucker rods H of the well by suitable means such as a flexible member 34. The flexible member may be a rope or cable looped over a saddle 35 at the forward end of the walkingbeam, the two ends of the flexible member being anchored to a suitable cross bar 36 at the upper end of the polish rod l8. The forward or working end of the walking-beam is provided with the usual arcuate means or mule-head 31 providing two channels for tangential engagement with the flexible member 34, the mule-head being concentric with the trunnions 36 of the vertical guide means.

This first form of my invention is based on the concept of restricting the vertical movement of the fulcrum pivot while permitting such pivot freedom for movement in a generally horizontal direction. My object here is to permit the arc of the mule-head to be shortened by causing the fulcrum pivot to shift toward the axis of the pump rods at both the upfier and lower ends of the pump stroke. In accordance with this con ception, at the rear end of the walking-beam the trunnions 21 are journaled in the upper ends of a pair of fulcrum links 38, the lower ends of which are keyed to a rocker shaft 39 journaled in a pair of bearings 40 on the platform 23. The fulcrum links limit the vertical movement of the fulcrum pivot of the walking-beam but constitute a flexible anchoring means since they permit lateral shifting of the fulcrum pivot.

The walking-beam is actuated by a pair of drive cranks 42 through a corresponding pair of connecting rods 43 engaging the trunnions 28. The vertical guide means 25 restricts the movement of the guide pivot of the walking-beam, i. e., the trunnions 30, the fulcrum pivot of the walking-beam shifting as required to permit such vertical movement. It is apparent that the walkingbeam has no fixed pivot and that the curvature of the path traversed by the drive pivot is much less in this arrangement than in the conventional arrangement for oscillating a walkingbeam about a fixed pivot.

While any type of vertical guide means may be provided for the guide pivot of the walkingbeam, as will be readily understood by those skilled in the art, I prefer in the present embodiment of my invention to incorporate the vertical guide means in the construction of a fluid-pressure counterbalance for the walking-beam, as will now be described.

The counterbalancing means includes a vertical hydraulic cylinder 44 and one or more, preferably two, associated upright tanks 45 and 46 together with a horizontal air receiver 41, the air receiver being within the frame 20 under the platform 23. The hydraulic cylinder 44 is open to the atmosphere at the top and opens at the bottom into a U-shaped chamber 43 that interconnects the two tanks 45 and 46. Mounted in the hydraulic cylinder 44 is a piston 49 extending upward from which is a piston rod 50. The piston rod is guided not only by the piston itself, but also by an upper guide means at the top end of the hydraulic cylinder comprising a spider 52 having a guide collar 53, and an intermediate guide means comprising a collar 54 at a lower level. Supported by the upper end of the piston rod 56 is an outer cylinder 55 that is telescoped over the hydraulic cylinder in spaced relation thereto. The aforementioned guide bearings 29, associated with the guide pivot of the walkingbeam, are carried by this cylinder so that the hydraulic cylinder, the piston, the piston rod, and the two guide means for the piston rod cooperate to restrict movement of the 'guide pivot of the walking-beam to a vertical path substantially parallel with the axis of the sucker rods in the well.

At least one of the two vertical upright tanks 45 and 46 is provided at the top with a relief pipe 56 having a relief valve 51, and both of the tanks are connected by a pipe 58 and a pipe 59 with the air receiver 41, the pipe 59 preferably being provided with a suitable cutoff valve 60. A suitable quantity of liquid, such as oil, within the U-shaped chamber 48 below the piston 49, surges up and down in the upright tanks 45 and 46 in accordance with the reciprocations of the piston, the liquid at its uppermost level in the tanks 45 and 46 being substantially below the pipe 58, the movement of the liquid upward being in opposition to the pressure of the air in the receiver 41.

Incorporated in the piston 49 may be a pump arrangement for returning to the liquid body any leakage upward past the piston. The drawings show a return pipe 62 extending above the piston and communicating with an inlet passage 63 leading to a vertical pump bore 64. A pump plunger 65 mounted to reciprocate in the bore 64 is normally held at an upper position by a spring 66. As the piston 49 approaches the upper limit of its range of movement, the return pipe 62 and the plunger 65 enter corresponding bores in the collar 54 and the plunger then impinges on a stop member 68 that causes the plunger to move downward in the vertical bore 64 to force any liquid therein outward through a check valve 69 into the fluid body below the piston. Since the return pipe 62 extends a substantial distance above the upper face of the piston, a substantial quantity of liquid will be retained in a pool on the upper side of the piston. This oil lubricates substantially the entire length of the piston rod by virtue of the fact that the upward movement of the piston'causes the collar 54 to be bathed in oil and the downward movement of the piston brings the upper por.ion of the piston rod 50 into contact with the collar 54, the collar being tapered .as shown, to retain oil around the periphery of the piston rod.

Any suitable power plant may be provided for actuating the walking-beam 24. In the preferred form of my invention an engtie 10 drives a train of gears carried by a frame 12 in a gear housing 13, the driving means including an engine pulley 14, a belt 15, and a large pulley 16 mounted on the exterior of the housing 13 on a shaft 11. A pair of spaced spur gears 18 keyed to the shaft 11 engages corresponding large gears 19 on a shaft 80. An intermediate spur gear 8I keyed to the shaft 80 meshes with a counterbalance gear 8. on a shaft 83. The counterbalance gear 82 in turn meshes with a larger gear 84 on a shaft 85 that carries the two drive cranks 42. i

Keyed to the opposite ends of the shaft 83 that carries the counterbalance gear 82 is a pair equalize the load on the engine 10. In the preferred form of my invention this auxiliary counterbalancing means operates against the pressure of the fluid-pressure arrangement already described.

In the arrangement suggested by the drawings, an auxiliary cylinder 81 mounted on the top of the gear housing 13 is connected toward its lower end with a pipe 88 that enters the side of the upright tank 46 and extends downward therein to terminate in the counterbalancing liquid well below the lowermost level of that liquid. A piston 89 mounted in the auxiliary cylinder 81 is connected with a piston rod 90 that extends upward through a suitable guide spider 92 at the top of the cylinder. Preferably the upper end of the auxiliary cylinder will be protected by an inverted cylinder 93 carried by the piston rod. Also carried by the piston rod is a bracket 94 in which is mounted a laterally extending shaft 95, which shaft is operatively connected with the counterbalancing cranks 86 by a pairof connecting rods 98. The angular relation of the counterbalancing cranks 86 to the drive cranks 42 is such that the counterbalance piston. is moved against counterbalance pressure as the .drive cranks 42 swing past their upper and lower dead centers. The downward movement of the auxiliary counterbalancing piston 89 forces oil into the maincounterbalancing system in opposition to the pressure from the air receiver .41. If desired, the piston 89 may be provided with means such as incorporated in' the main piston 49 to return oil leaking upward past the piston.

Automatic means to maintain the pressure in the air receiver 41 may be provided in a manner now to be described. A suitable air pump 98 alongside the auxiliary cylinder 81 has an operating piston rod 99 connected to a bracket I00 extending laterally from the aforementioned bracket 94 at the top of the pitton rod .90 so that the air pump is operated by the reciprocations of the auxiliary counterbalancing means. Air from the pump-98 is delivered into a small highpressure receiver I02 through a delivery pipe I03 equipped with a check valve I04 and a pressure gauge I05. The air receiver has the usual safety valve I06 and is connected with the horizontal air receiver 41 through a pipe I01. The pipe I01 .below that point.

is adjusted to step down that pressure to the V has a reduction valve I08 below which is a second pressure gauge I09.

Preferably the displacement of the air pump 98 will be such as to maintain the pressure in the tank I02 at a value substantially above any counterbalance pressure required in service. This pressure may be varied at will by varying the point at which the piston rod 99 is connected to the bracket I00. Whenever the pressure in the tank I02 reaches the limit determined by the displacement of the pump 98, the delivery of air into the tank I03 will cease automatically but will be resumed whenever the pressure in the tank drops The pressure regulator I08 particular counterbalancing pressure required by the load on the walking-beam.

The operation of my pumping unit may readily be understood from the foregoing description.

It will be noted that by virtue of the fact that the guide pivot of the walking-beam is moved in an absolutely straight line, the mule-head 31 concentric with the guide pivot transmits forces to the well pump along the ax s of the string or pump rods at all angles of the walking-beam.

. It will be noted that in Fig. 1 the fulcrum pivot 21 shifts laterally in a slightly arcuate path. Instead of the fulcrum links 38, a cross-head I I2 (Fig. 4) operating between a pair of horizontal guides I I3 may be provided to limit the fulcrum pivot of the walking-beam to strictly horizontal movement, the walking-beam extending to opposite sides of the cross-head and being connected to a pivot pin II4 extending through the cross-. head. It is apparent that the arrangement to which Figs, 1 to 4 refer transmits force in the desired direction with a much shorter mule-head than would be necessary were the walking-beam oscillated about a fixed pivot in the conventional manner. a

In the second form of my invention the fulcrum pivot at the opposite end of the walkingbeam from the working end is provided with arcuate means in rolling engagement with a fixed member, the walking-beam being provided, for example, with a second mule-head at the fulcrum pivot in tangential engagement with an anchored flexible member, whereby the effective fulcrum point simultaneously reciprocates vertically and travels around the curve of the secondmule-head,

the vertical movement of the guide'pivot being thus accommodated by rolling action at the fulcrum end of the walking-beam. This second form of my invent on is based on the concept of dividing the function of a mule-head between two mule-heads on opposite ends of the walkingbe'am, whereby the arcuate extent of either mule head may be reduced toone-half or less the arcuate extent of a single mule-head. My invention in this second form may be regardedin still another aspect, namely, as the concept of applying to a walking-beam construction the principle of a giant sheave on a vert'cally shifting axis with an anchored flexible member extending over tangential engagement with a second flexible member I28, but this second flexible member is anchored at a fixed point I 29. This arrangement of a mule-head and anchored flexible means may be regarded as providing a fulcrum pivot for the walking-beam, which fulcrum pivot shifts vertically to a limited extent when the walkingbeam is oscillated by force transmitted through the connecting rods I30.

In the preferred form of my invention, the secondary cylinder 81 is connected through the pipe 88to the main fluid-pressure counterbalancing system. A feature of my invention is the conception of completely separating the auxiliary cylinder 81 from the main fluid-pressure system and utilizing the reciprocation of the piston 89 in that cylinder not only for the purpose of counterbalancing the crank 86, but also for the purpose of pumping air to the main fluid-pressure system; Such a modification is suggested by Fig. 1a in which the piston 89a that reciprocates in the auxiliary cylinder 81a is provided with an air intake valve I3I. The. pipe 88 of Fig. 1 as well as the air pump 98 are omitted. The pipe I03a leading to the high-pressure receiver I02a is connected to the bottom of the cylinder 81a. This pipe is equipped with a check-valve I04a, a pressure gauge I05a, and a pressure regulator I32, the pressure regulator being between the check-valve and gauge.

As the piston 88a descends, it compresses air in the cylinder 81a. Whether air so compressed passes to the high-pressure cylinder tank I020. depends upon the setting of the-pressure regulator I32 and the relation of that setting to the pressure in the high-pressure tank. It is apparent that various adjustments may be made to vary the pumping action in the reciprocation of the piston 89a and the amount of energy delivered back to the crank 86 when the piston 89a moves upward. In one mode of. operation the auxiliary counterbalance arrangement of Fig. 1a would automatically deliver air into the highpressure tank I02a whenever the pressure in that tank falls below a predetermined value. In another mode of operation the pressure regulator I32 would serve, in effect, as a cutoff valve that will be normally closed to permit thevair in the cylinder 81a to reach relatively high pressures for counterbalancing purposes; whenever required, as indicated by the gauge I05a, the operator would adjust the pressure regulator I32 for a temporary period of pumping operation.

While usually my invention will be employed for reciprocating a truly vertical polish rod, the path of the guide pivot of the walking-beam being parallel to the-axis of said polish rod, in some installations where the top of the well is out of line, my invention will be employed for nonvertical reciprocation and the path of the walking-beam guide pivot will be non-parallel to the axis of the polish rod. My invention may be readily adapted to such a situation by making the curvature of. the mule-head such that the I mule-head will be throughout its range of movement substantially tangential to the axis of the polish rod. Illustrating such an arrangement, Fig. 6 shows a walking-beam I35 pivotally connected at one end to a pair of fulcrum links I36 and connected at the other end by a flexible member I31 to a polish rod I38. It will be noted that this polish rod and the flexible member I31 coaxial therewith are out of vertical alignment, whereas, the vertical guide means I39 is disposed to move the guide pivot I40 of the walking-beam in a substantially vertical path. The profile configuration of the mule-head I4I at the working end of a walking-beam is, therefore, an irregular curve that at all points in the reciprocation of the walking-beam is substantially tangential to the axis of the polish rod I38.

In another form of my invention I may substitute a linkage arrangement for the mule-head at the working end of the walking-beam, as sugwalking-beam I43 pivoted to a pair of. fulcrum links I44 and driven by a pair of connecting rods I45 previously described. The vertical guide means I46 has trunnions I41 journaled in bearings I48 of the walking-beam to provide the usual guide pivot.

Mounted on a shaft I49 at the outer end of the walking-beam is a rocker member generally designated I50 that includes two arms I5I mounted on the shaft I49 and interconnected at their upper ends by a rod I52. The upper end of the rocker member I50 is tied to the vertical guide means I46 by a link I53 that rotatably engages .the rod I52 and a pin I54 that is carried by a bracket I55 on the vertical guide means. The lower end of the rocker member I50 is connected to the polish rod I56 by a suitable bearing means generally designated I51.

The bearing means I51, preferably, as shown in the drawings, incorporates a bearing construction described in my copending application Serial No. 156,980, filed August 2, 1937, entitled Method of and apparatus for lubricating walking beam bearings. The drawings show two bearing housings I58, one at the lower end of each of the arms I5I of the rocker member, each of the housings being made in two parts connected by a suitable bolt means I59. Within each of these housings is a rotary bearing member I60 having a plurality of. eccentric sections that rest on a complementary journal seat I6 I the two rotary hearing members being interconnected by a common rocker shaft I62. The polish rod I56 may be connected to the shaft I62 in any suitable man ner. In the drawings it extends diametrically through the shaft I62 and terminates in nuts I63 that rest against a suitable washer or collar I64.

Fig. 9 indicates how the rocker member I50 and the link I53 may be so related to the walkingbeam and to the vertical guide means as to result in straight-line movement of the bearing I51. At the uppermost position of the working end of the beam the bearing is at the position I49a, the positions of the link I53 and the rocker arm being indicated by dotted lines; when the walkingbeam is approximately horizontal the bearing is at I49b, the link and rocker member being at positions indicated by dot-dash lines; at the lowermost position of the working end of the walking-beam, the link and rocker arm are in the dash-line positions, placing the bearing member at I490. For a ten foot pump stroke the vertical guide means I46 may, for example, be reciprocated seven feet and the walking-beam oscillated to move the bearing I51 an additional three feet in the straight line indicated.

I have shown and described preferred embodiments of my invention in specific detail for the purposes of disclosure and to illustrate the principles involved. It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit of my invention. I reserve the right to all such changes and modifications that propgested by Figs. 7 to 9. The drawings show a VII erly come within the scope of myappended claims.

I claim as my invention:

In a device of the character described for reciprocating a member in a well, the combination of: a walking-beam operatively connected with said member; means pivotally connected with the walking-beam to raise and lower the walking-beam; means flexibly anchoring a fulcrum point of the walking-beam to cause the beam to oscillate when so raised and lowered; guide means restricting one point of the walkingbeam to substantially straight line motion; and a counterbalance means operatively connected with the walking-beam at said guided point.

2. In a device of the character described for reciprocating a load member in'substantially a straight line, the combination of a walkingbeam; means pivotally connected with the walking-beam to raise and lower the walking-beam; means flexibly anchoring a fulcrum point of the walking-beam to cause the beam to oscillate when so raised and lowered; guide means restricting one point of the walking-beam to substantially straight line motion; means at the working end of the walking-beam to compensate for movement thereof with respect to said straight line; and means interconnecting said load member and said compensating means.

3. Means of the character described for transmitting force in substantially a straight line to a load member, said means comprising: guide means adapted to reciprocate in a substantially straight line; a rocker member pivoted at an in termediate point to said guide means, said rocker member having a fulcrum end and a working end; means extending along said first-mentioned straight line for interconnecting said load member and the working end of said rocker; means at said working end of the rocker member in engagement with said interconnecting means to compensate for the arcuate path of said working end; anchor. means connected with the fulcrum end of the rocker member to permit shifting thereof as required by said guide means; and power means to oscillate said rocker member.

4. Means of the character described for transmitting force in a substantially straight line to a driven member to move the driven member periodically in opposition to a load, said means comprising: guidemeans adapted to reciprocate in a path substantially parallel with said straight line; a rocker member pivoted at an intermediate point to said guide means, said rocker member having a fulcrum endand a working end, the latter end extending to said straight line; means extending along said straight line interconnecting said load member and the working end of said rocker; arcuate means at said working end of the rocker member in tangential engagement with said interconnecting means, said arcuate means being substantially concentric to the pivotal connection of the rocker member with said guide means; flexible anchoring means connected to the fulcrum end of the rocker member; power means to rock said rocker means in the direction opposed to said load; and counterbalancing means connected with said rocker means to oppose the opposite movement of the rocker member.

5. Means of the character described for transmitting force in substantially a straight line to a driven member to move the driven member periodically in opposition to a load, said means comprising? guide means adapted to reciprocate in a path substantially parallel with said straight line; a rocker member pivoted at an intermediate point to said guide means, said rocker member having a fulcrum end and aworking end, the latter end extending to said straight line; means extending along said straight line interconnecting said load member and the working end ofsaid L rocker; arcuate means at said working end of the rocker member in tangential engagement with said interconnecting means, said arcuate means being substantially concentric to the pivotal connection of the rocker member with said guide means; anchor means connected with the fulcrum end of the rocker member to permit shifting thereof as required by said guide means; power means to rock said rocker means in the direction opposed to said load; and counterbalancing means acting upon said guided point of the rocker member to oppose the opposite movement of the rocker member.

6. Means for actuating pump rods or the like in a well, said means including: a beam having a guide pivot and a fulcrum pivot; guide means providing a substantially straight path for said guide pivot; anchor means for said fulcrum pivot adapted to permit lateral shifting thereof as required for vertical movement of the guide pivot; arcuate means on said beam concentric to said guide pivot and. substantially tangential to said pump rods; means engaged by said arcuate means to operatively connect said beam with the pump rods; and power means to move the beam upward against the load on said pump rods.

7. Means for actuating pump rods or the like in a well, said means including: a beam having a guide pivot dividing the beam into forward and rearward arms; guide means to limit movement of said guide pivot to a substantially vertical path; flexible means substantially in alignment with the axis of said pump rods interconnecting the pump rods and the forward arm of the beam; means on the forward arm of the beam engaged with said interconnecting means and adapted to compensate for the arcuate character of the arm movement; a second flexible means having its lower end anchored and its upper end connected to the rearward arm of the beam; arcuate means onsaid rearward arm of the beam concentric with said guide pivot in tangential engagement with said flexible means; and means to actuate said beam.

8. Means'for actuating pump rods or the like in a well, said means including: a beam having a guide pivot dividing the beam into forward and rearward arms; guide means to limit movement of said guide pivot to a substantially verti'cal path; flexible means substantially in alignment with the axis of said pump rods interconnecting the pump rods and the forward arm of the beam; arcuate means on the forward arm of the beam concentric with said guide pivot in tangential engagement with said flexible means; a second flexible means having its lower end anchored and its upper end connected to the rearward arm of the beam; arcuate means on said rearward arm of the beam concentric with said' guide pivot in tangential engagement with said second flexible means; and means to actuate said beam.

9. Means for actuating pump rods or the like in a well, said means including: a vertically movable fluld-pressure-actuated counterbalancing means exerting force in an upward direction; a rocker member pivotally mounted on said coun terbalancing means; means substantially coaxial with said pump rods interconnecting the pump rods and the beam; means on the rocker member in engagement with said interconnecting means to compensate for curvature in the movement of the rocker member; fulcrum means connected with said beam in a flexible manner to permit vertical movement of the pivotal point of the beam; a drive crank operatively connected with the beam to lift the beam in opposition to the load on said pump rods; power means to actuate said drive crank; a counterbalancing crank operatively connected with said drive crank to make two revolutions for one revolution of the drive crank; and fluid-pressure-actuated counterbalancing means operatively connected to said counterbalancing crank to equalize the load on said power means.

10. Means of the character described for actuating a load member in a well, said means including: a walking-beam operatively connected with said load member; a drive crank operatively connected with the beam; power means to actuate the drive crank; a fluid-pressure counterbalancing means adapted to oppose the downward movement of the beam to equalize the load on said drive crank; a counterbalance crank operatively connected with said drive crank to make two revolutions for every revolution of the drive crank; and fluid-pressure counterbalancing means adapted to oppose movement of said counterbalancing crank in one direction to equalize the load on said power means.

11. Means of the character described for actuating a substantially vertical movable member in a well,.said means including: a beam having a pivot dividing the beam into a forward arm and a rearward arm; means to guide said pivot along a substantially vertical path; means substantially coaxial with the well interconnecting said means in the well with the forward arm of said beam; means on the beam in engagement with said interconnecting means to compensate for curvature in the path of said end of the rocker member; means anchoring the rearward arm of the beam in a flexible manner to permit the vertical movement of said pivot point of the beam; a drive crank operatively connected with the beam to move the beam in opposition to the downward force transmitted by said interconnecting means; power means to actuate the drive crank; a counterbalance crank operatively connected with said drive crank to make two revolutions for every revolution of the drive crank; and fluid-pressure counterbalancing means adapted to oppose the downward movement of the beam to equalize the load on said drive crank and adapted also to oppose movement of said counterbalancing crank in one direction to equalize the load on said power means.

12. Means of the character described for actuating a load member in a well, said means including: a walking-beam operatively connected with said load member; a drive crank operatively connected with the beam; power means to actuate the drive crank; a primary fluid-pressure counterbalancing means adapted to oppose the downward movement of the beam to equalize the load on said drive crank; a counterbalance crank operatively connected with said drive crank to make two revolutions for every revolution of the drive crank; and auxiliary fluid-pressure counterbalancing means adapted to oppose movement of said counterbalancing crank in one direction to equalize the load on said power means, said auxiliary counterbalancing means being constructed to serve as a pump for maintaining pressure in said primary counterbalancing means.

13. In a device of the character. described for reciprocating a load member in substantially a straight line, the combination of: a walkingbeam support adapted to reciprocate in substantially a straight line; a walking-beam pivotally mounted on said support; a rocker member mounted on said walking-beam; means interconnecting one end of said rocker member with said load; and a link interconnecting the other end of the rocker member and said walkingbeamsupport, said link and rocker member being so dimensioned and disposed as to cause the end of the rocker member connected with said load to move in substantially a straight line.

14. In a device of the character described for reciprocating a load member in substantially a straight line, the combination of z a walkingbeam having its working end connected to said member substantially in said straight line; power v means to raise and lower said walking-beam; means flexibly anchoring a fulcrum point of the walking-beam to cause the beam to oscillate when so raised and lowered; means connected to the walking-beam including a cylinder and a cooperating member slidingly telescoped therein to serve both as a guide to restrict a point of the walking-beam to rectilinear movement and as a counterbalance for the load imposed on the walking-beam; and means at the working end of the walking-beam to compensate for arcuate departure thereof from said straight line.

WALTER E. SAXE. 

